Electric brake



A. W. McAULY.

ELECTRIC BRAKE.

APPLICATION FILED JAN. 2s, |920. y 1,407,207. Patented Feb. 21, 1922.

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@e 54 2 www ATTORNEYS A. W. McAULY.

ELECTRIC BRAKE. APPLlc/wmn man 1AN.26. 1920.

1 ,407,20'7, Patented Eeb. 21, 1922.

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ATToRNEYs To all/ whom t may concern.' Y

Be it known that I, ARTHUR W. MCAULY,

'a citizen ofthe-United States, residing in Oakmont, inthe countyfof Allegheny and State` 'of Pennsylvania, have invented a new Y andv useful Improvement in Electric Brakes, of which the followingis a specification.

'This' invention relates in general to electric brakes andvhas more particular reference to brakes ofthis character wherein the braking action is performed 4by brake lshoes acting against opposite sides of a brake drum.A

As is well known springs or weights are usually provided toy force the shoes into braking engagement with the drum and 1n electrical brakes magneticV meansv are employed to act in opposition tothe weights or springs to release the brake and hold it in off position. Prior to mypresent invention most of the' magnetic means employedha's consisted of a 'single magnet which byl the movement of its armature acted through a system of levers to apply the releasing force to diametrically opposite brake shoes. This arrangement required a considerablemovement'of the armature 0f the magnet and since the magnetic forcefelt 'by the armatures varies inversely as the square of thedistance through which such force must act the springs or weights-used were relatively the parts of which will be so constructed and arranged that a thick brake lining may be used, the arrangement Vbeing such that adjustment may be readily effected as wear occurs. L

Another important object of the invention is the construction and arrangement of thev several parts of an electric brake of the char-V acter describedA so that thev extent of Vwear Specification of Letters vPaten-t.

andthe need for adjustment will bifiai'alwaysr'`v` apparent by merely :glancing at thev apparatus and without requiring anyof thefparts to be removed for the purpose ofinspecti0n.

Y ARTHURAW. Mge-Unir, kor oAKivroN'r, rENNsYLviIIA. y

Y Iia'tented;Feb.` 21, '1922. Appucation sled Janary 2s, 192m serial no. 3754.138. f 4

the clearancebetween the shoesand druinat all points may be readily equalized and ,the

Possibility of uneven wear ofthe liningthus materially reduced. .Y f

A further objectof the invention is the' provision-of an electric brake that will be readily adjustable'tof compensate. for :weari of the parts @ofthe apparatus other than the v brake lining. Y y I I A still further and important objectof the invention is the provision of anelectrlic brake that will 'permit of the removal of'the drum. and shaft o n4 whichl itis `mounted with a minimum disassembling ofthe brake and other parts; ,Y f f still further and importantobject of the invention is theprovsion of fanelectric', brake of extremely simpleconstruetion,all

the parts being 'in readily accessible position -I v and proportioned sofasto" provide great-me"-V chanieal strength. l. fv .I

Anotherobject o`f my invention vis'the con'- struction and arrangement` of the magnetic means -fo'r releasing the brake .anda the mounting therefor in such manner that them'agne'tic coils need not accurately conform to the housing or frame in 'which it is placed and will not be subjected topweardue to its sliding back fand; forthin such frame;

Otherwise stated the v,inventionY has for anobject' the provision kof magnetic .coils so protected that wearjof the insulation` and@ consequent grounding lwillbe obviated.

Another object 'of the,:inventionisfthe provision of` an electriebr'ake'so constructedVv and arranged that repairs,"replacement and readjustment may be readily made.

Other objects and advantages of the vention will be' apparent as it isbetter'under-v VV; n

stood Vfrom the following y description, 'which4 taken in connection with Atheaccompanying drawings discloses apre-ferred embod-imentv thereof. :Y

On the drawings, y .fz f r i. Figure lis anfendelevation voff-an elec# rus tric 'brake `embodying my presentfinven- V Y tion; y Y Figc@isatopfplanviewthereof;

Fig. -3 is a section taken substantially on the line 3 3 of Fig. 1;

Fig. 4c is a side elevation of the same;

F ig. 5 is a partial detail section on an enlarged scale showing the adjustable connection between each magnet support and the base; and

Fig. 6 is a diagrammatic showing of the wiring.

For the purpose of illustrating my invention I have lshown on the drawing an apparatus in which it is embodied- The drawing discloses-.apart of a shaft 11 which may be the motor shaft or which may be taken to be part of any suitable apparatus,V as for example an electric crane, said shaft having bearings as the other parts of theapparatus mayrenderconvenie'nt. The shaft 11 carriesa brake drum 12 of any usual or preferred construction.

Two brake shoes 13 of arcuate`v form are provided at opposite sides of the brake drum andeachis mounted'upon a lever 14a by pivot pins 15. The levers 141C are pivotally mounted upon slides 16 by pins 17. At the top, the levers 11-are slotted or'bifurcated at 18 Vto receive a rodV 19. On the ends of this yrod are :positioned springs 2l bearing at their inner ends against the levers 14 and at their outer ends againstwaslr ers 22 held in place by nuts 23 threaded. on the ends of therod 19. Lock nuts are preferably also provided. The springs normally'force the levers toward each other to in turn force the brake shoes toward the drum and apply the brakes.-

Electrical means are provided tomove the shoes against the' force of the springs away from the drum to release the brake and hold it in released position. This electrical means comprises an electromagnet located at and behind each brake shoe and in position to attract the lever 14 whichv acts as an yarmature for the magnet. Eachl magnet comprises a core 25 upon which is wound coils of copper wire 26. The coil is carried'in and supportedjby a yoke 27 forming a part of the slide'16. This yoke extends up and over the magnet inthe `form of an arm'28 to adjacent the appropriate lever 14E upon which is provided lifts 29 extending over the end Vof the arm and spaced slightly therefrom. A

The magnet coils are wound upon insulating tubes 2O having outturned flanges 10 at the outer ends, the whole being readily removable from each core as a unit. This arrangement prevents removing of the mag series with amotor driving the apparatus of which thesha-ft 11 forms a part when such a motor is employed; and when it is desired to releasethe brake andy cause the shaft 11 to first removing the springs and rod 19, thel pivotal mountings of the brake shoes permitting them to move out Vof the way. More,

over it will alsobe noted that lowering of' the shaft andthe drum as a result of wear in the bearings or readjustment of them .will not appreciably effect the character of the engagement between the shoes and the drum. ln order that there shall be an even clearance between the drum andshoeswhen the brake is offy l provide a set screw 31 ex tending into the back of each shoe and adapted to engage the forward space of its lever .-l/l., .Aaloclr nut 32 is preferably pro vided to hold the set screw in adjusted relation.. 1

Means are provided for adjusting the brake shoes toward the drum as a brake shoe lining wears. These means in the present instance are the slides 16. Each slide is provided with a pair of arms or lugs 33 extending down into registration with a recess 34 slidably fitting therein. At the inner end of this, slide is a vertically'extending web 37 at the inside of the recess 34. A cap screw 39 is arranged through the lug 33 and threaded through the vertical web 37 at the inner end of the recess in the main support. Extending 'through slotted recesses in the sides of the main support are lateral clamping screws 40 screwed into the lugs 33 of the slides 16 and adapted to clamp said lugs and the slides 16 ixedly to the recessed frame member. By loosening these clamping screws 4l()V and turning the screwv39 the slide 16 may be moved inwardly or outwardly with respect' to the recess of the main support, its outward movement being effected by a spring4 Ll1 Vas the bolt 39 is loosened. The springs 41 are provided to hold the slides 16 as far separated as the position ofthe cap screws 39 will permit. Adjustment is effected by adjusting the. cap screw to move the yolres in and out. This arrangement permits the use of extremely light brake linings for the brake shoes and the making of adjustment as they wear down. lt will be noted that the movement of the brake shoes in the adjustment inoaaov" Y The extent of movement of each brake shoe is exactly equal to the space between the armature and magnet when the brake is applied and since this space is always visible Vit will indicate the extent of wear so that need for adjustment will always be apparent.

The brake embodying my invention and shown on the drawing may be used with reduced efficiency should one of the brake shoes be out of use. rlhe squared construction at the bottom of each armature lever limits the brake applying movement of the armature so that operation may 'still be accomplished when'one brake shoe is absent.

It will also be apparent that the mounting of the armatures in the manner described reduces materially the wear on pivot pins 17. The whole construction is simple and the parts all easily accessible for repair, replacement and readj ustment.

F ig. 6 shows a possible simple wiring diagram. Wires 5l and 52 indicate line or service wires and may be considered a. source of current. Wire 5l is connected to one side of the motor indicated at 53, and the otherf side of this motor is connected by wire 54 with one side of one coil 26. Vire 55 connects the other side of this coil with .one side of the other coil 26 and the other side of this coil is in turn connected with wire 52 so that the motor and the two coilsV are arranged in series.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacriicing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

l. In an electric brake, the combination of a brake drum, pivotally mounted brake shoes adapted to bear thereagainst in braking,

means normally forcing said shoes against said drum, electrical means for withdraw-L ing said shoes, and means for bodily adjusting said shoes and said electrical means radially of the drum to compensate for wear of the brake shoe lining.

2. In an electric brake, the combination of a brakedrum, pivotally mounted brake shoes adapted to bear thereagainst in breaking, means normally forcing said shoes against said drum, electrical means for withdrawing said shoes, and means for bodily adjusting said shoes and said electrical means to compensate for wear ofthe brake shoe lining in a straight line movement radially toward and from saidy drum.y

Inan electric brake in'combination:r a frame,`abrakingdrum,magnets mountedv in said frame, arma-ture levers'pivotally mount-vv ed'frelativeto said frame and-.adjustable to? wards and from said drum and cooperating with said magnets, brakeA shoes pivotally connected with said armature levers, brake actuating means carried by said levers to normally maintain said shoes in braking engagement with said drum, said brake actuating means being detachable to eiiect the re- .moval of said drum from said brake shoes and said frame without disturbing the braking adjustment of said armature levers.

4. In an electric brake inj combination: a frame, a braking drum,magnets mounted in said frame, armaturel levers pivotally mounted in said'frame and cooperating with said magnets, brake shoes pivotally connected with said armature levers, means carried by said levers to normally maintain said shoes inbraking engagement with said dru1n,said` armature levers and said magnets. being adjustable horizontally towards and from said drum to compensate for wear vupon said brake shoes.

5. In an electricv brake in combination: a frame, a braking drum, a pair of armature pivots being adjustable towards and from each other and said drum, a pair of brake shoesy pivotally mounted on said armaturev levers on opposite sides of said drum, means carried by each of said `levers to normally maintain said shoes with braking pressure on said drum, and a pair of magnets carried by said frame and arranged each to operate one of the armature levers.'

said drum, said pivotal connections of thel brake shoes with the arifnature levers being detachable to effect the-removal of said brake shoes without disturbing the braking adjustment of said armature levers.

7. In an electric brake, in combination with a frame: a brake drum, a pairof brake shoes adapted to bear against said drum*v in braking, a pair of armature levers pivotally mounted onsaid frame and having a pivotal connection with said brake shoes, mechanical `levers pivotally mounted relative to said Y frame on opposite sides of the drum, saidV means carried by the upper ends of said armature levers adapted to normally main- Lemgo? tain said levers and brake shoes in braking to decrease the distance between said levers engagement with said drum', and magnets and said drum, Without decreasing the dismounted in said frame adapted When enertance between said levers and said magnets7 10 gized to Withdrawsaicl levers and braking to compensate for Wear upon said brake shoes from braking position, said armature shoes. Y f

levers and said magnets being mounted for o horizontal adjustment together in said frame ARTHUR W. MGAULY. 

